Taking damage after timing out Senator phase 2

achievementsmetal-gear-rising-revengeance

I'm going for the no-damage achievement against the Senator, and I'm aware that to avoid damage in phase 2 I have to time it out. But both times I've managed to trigger the unavoidable move that immediately moves to phase 3, it's dealt damage! Raiden goes from 190% to just over 150% hp as the transition to the next phase begins. I haven't cleared phase 3 after this yet but I have to assume that I won't get the no damage tag. Is there something I have to do to prevent the unavoidable move from dealing damage? Am I mistaken in thinking that the damage I took will prevent the no-damage bonus and achievement?

I'm playing on PC and entered the fight from the chapter select menu.

Best Answer

As time advances, the second phase of the Senator fight will flip a hidden switch that advances the phase the next time Raiden is knocked over. At about the same time, Senator Armstrong will begin using a move where he charges forward and kicks. This move deals damage, knocks Raiden over, but can be dodged. I mistook this attack for the unavoidable no-damage move, which is a ground slam with a very long windup. Both attacks that deal damage and the special unavoidable no-damage attack will trigger the next phase - if you get knocked over by a damaging move the checkpoint saves instantly and you have to replay phase 1 for no-damage.